Inhibition of flow-induced corrosion and erosion-corrosion for carbon steel pipe work from an offshore oil and gas facility

A flow-induced corrosion and erosion-corrosion investigation was conducted to determine the degradation rates and mechanisms that had been experienced in service in the pipe work of an offshore facility. The investigation reviewed the flow-induced corrosion and erosion-corrosion performance of the carbon steel parent metal of the pipe work in comparison to the heat-affected zone (HAZ) and the nickel-molybdenum weld material. The program of experiments assessed the potential of two corrosion inhibitors to control adequately the material degradation caused by static corrosion, flow-induced corrosion, and erosion-corrosion on the three regions. Static corrosion tests were performed using linear polarization in carbon dioxide (CO2)-saturated conditions. Flow-induced corrosion and erosion-corrosion experiments were conducted using a submerged impinging jet (SIJ) in CO2-saturated conditions at a fluid velocity of 7 m/s with sand loadings of 0 mg/L and 100 mg/L. The effects of flow-induced corrosion and erosion-corrosion were studied using gravimetric techniques. Mechanisms were discussed based upon results obtained from micro-structural studies.